This invention relates to an industrial cable reel apparatus for the storage and support of flexible cables upon a rotatable cable support having a spring-loaded rewind motor means coupled to the support.
Many electrical as well as fluid power systems require relatively long cables for transmission of power between a power supply and a remote load device. The various applications may require relatively long vertical extensions or horizontal extensions of the cable. Elongated cables which are not confined are subject to damage or destruction in most industrial applications and the like.
A steel mill installation is a typical installation wherein relatively long vertical and/or horizontal cable extensions are required. Vertical lifting apparatus may, for example, require application of power to a lifting head. In such a vertical lift a cable is extended and moved vertically with the lifting device. In other applications, an overhead crane-like unit may be mounted on trolley unit. Power may be supplied to the trolley unit using an elongated flexible cable of sufficient length to extend between a power supply connection and the remotest location of the trolley unit. In other applications encountered in a steel mill, various extension and retrieval requirements are created which require corresponding movement of a power cable or the like.
Similar cable specifications are encountered in other industrial applications.
Cable reel apparatus is available to contain and store a flexible cable while permitting the extension and retrieval thereof as the distance between the supply device and the connected device changes. As employed herein, the terminology "cable" will generically identify elongated flexible elements, including electrical cables, pneumatic and hydraulic hoses and other like flexible elements which can be conveniently wound and unwound on a cable reel support and particularly a cable spool.
Although each particular installation requires selection of a particular design, the cable reel apparatus is basically of a similar construction and generally includes a rotatably mounted spool unit defining a cable support means on which the cable is wound and unwound. The spool is rotatably mounted in an appropriate mounting or support structure, which may be a mobile unit or a fixed support structure. A power connector unit is connected to the support and located to the one side of the spool normally on a common axis. A rotary power coupling unit is mounted within the collector unit and includes a power connecting means which extends through the assembly to a connection to the inner end of the cable, thereby permitting rotation of the spool and cable relative to the collector and the fixed supply. For example, in an electrical system a brush and ring contact assembly will provide for convenient electrical power connection. The cable reel apparatus further includes a return means which may be an electric motor or a spring motor unit. The spring motor unit, generally is in the form of a spiral clock spring, secured to the opposite side of the support from the collector and coupled through a suitable lubricated gear coupling means to the spool. The spiral spring unit is constructed and arranged such that the spiral springs are stressed with the spring forces arranged to rotate the spool to wind the cable onto the spool. The force is such however, that the cable can be unwound from the spool by pulling thereon, with the spool rotating and tensioning the spiral spring unit. When the load on the cable is released, the spring unit serves to provide a controlled rewind of the cable onto the spool.
Although cable reel apparatus is available in compact, rugged and reliable structures for use in industrial environments, such as in a steel mill and the like, the mechanical construction inherently may require periodic maintenance and service and the like. In some cases, a cable reel apparatus may require adaptation to a different load requirement. In industrial environments, substantial spring forces must be available and created by the spiral spring units. For example, in a steel mill, electrical 600 volt cables may have to extend for hundreds of feet in any given application. A plurality of paralleled spring or series units may be connected to the cable reel to create the desired driving force for moving of the cable. To service or modify the unit therefore generally requires complete disconnection of the cable hook-up in order to permit release of the tension on the spring mechanism. The required disconnection may be costly and time consuming, as well as inconvenient.
There is therefore a need for a safe but reliable means for releasing of the spring tension while maintaining of the cable system hook-up in place.